Partition walls made up of units comprising panels, raceways, baseboards and even the whole cubicles with shelves, desks, and the like, have long been known. Also units of this type have been anchored together by various types of fastening means along their edges, even including slide interfitting C-cross-sectional strips. Furthermore, angle blocks in mitered corners for fastening frame strips together are known. Also bolt-and-nut-type levellers have been long employed for the bottom edge or baseboard units of partition walls. Usually, the fasteners for the vertical portions of the panels making up the walls is different from that employed for horizontal raceways and/or baseboards so that panel units are often usable in a given direction. Previously a common means for fastening such units and their mitered corners of frames involved welding and/or complicated and expensive tools for assembly.